HEAT PUMP WITH MAGNETO CALORIC MATERIALS AND VARIABLE MAGNETIC FIELD STRENGTH

• US 20140305137A1
• Filed: 04/16/2013
• Published: 10/16/2014
• Est. Priority Date: 04/16/2013
• Status: Active Grant

• Current Assignee: Haier US Appliance Solutions, Inc. DBA GE Appliances (Haier Group Company)
• Original Assignee: General Electric Company
• Inventors: Benedict, Michael Alexander
• Granted Patent: US 9,625,185 B2
• Time in Patent Office: Days
• US Class Current: 62/3.1
• CPC Class Codes: F25B 21/00 Machines, plants or systems, using electric or magnetic effects
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A heat pump system is provided that uses MCM for heating or cooling. A magnetic field of decreasing flux intensity is used to decrease power consumption and reduce e.g., the size of one or more magnetic devices associated with creating the magnetic field. In one exemplary embodiment, the heat pump is constructed from a continuously rotating regenerator where MCM is cycled in and out of a magnetic field in a continuous manner and a heat transfer fluid is circulated therethrough to provide for heat transfer in a cyclic manner. The magneto caloric material may include stages having different Curie temperature ranges. An appliance using such a heat pump system is also provided. The heat pump may also be used in other applications for heating, cooling, or both.

Claims

1. A heat pump, comprising:

a plurality of stages arranged sequentially along a predetermined direction, each stage comprising magneto caloric material having a Curie temperature range, the plurality of stages arranged so that the Curie temperature ranges of the plurality of stages increase along the predetermined direction; and

a magnetic device positioned adjacent to the plurality of stages, the magnetic device configured to subject the plurality of stages to a magnetic field of decreasing magnetic flux along the predetermined direction.

2. A heat pump as in claim 1, wherein the magnetic flux decreases in a substantially linear manner along the predetermined direction as the Curie temperature ranges increase along the predetermined direction

3. A heat pump as in claim 1, wherein the rate of decrease of the magnetic flux of the magnetic field along the predetermined direction is substantially equal to the absolute value of the rate of increase in the Curie temperature ranges of the plurality of stages along the predetermined direction.

4. A heat pump as in claim 1, wherein the magnetic device comprises one or more magnets.

5. A heat pump as in claim 3, wherein the one or more magnets has a thickness along a direction that is substantially orthogonal to the predetermined direction of the plurality of stages, the thickness of the one or more magnets decreasing along the predetermined direction.

6. A heat pump as in claim 1, wherein the Curie temperature ranges of the plurality of stages overlap between stages that are adjacent along the predetermined direction.

7. A heat pump as in claim 1, wherein the magnetic device, the plurality of stages, or both, are configured for cycling the plurality of stages in and out of the magnetic field during operation of the heat pump.

8. A heat pump as in claim 1, wherein the magnetic device comprises an electromagnet.

9. A refrigerator appliance comprising the heat pump of claim 1.

10. A heat pump system, comprising:

a regenerator housing defining a circumferential direction and rotatable about an axial direction, the axial direction extending between a first end and a second end of the regenerator housing, the regenerator housing comprising a plurality of chambers with each chamber extending longitudinally along the axial direction between a pair of openings, the plurality of chambers arranged proximate to each other along the circumferential direction;

a plurality of working units, each working unit positioned within one of the plurality of chambers and extending along the axial direction, each working unit comprising a plurality of stages arranged sequentially along the axial direction, each stage comprising magneto caloric material having a Curie temperature range, the plurality of stages arranged so that the Curie temperature ranges of the plurality of stages increase along the axial direction;

a pair of valves comprising a first valve attached to the first end of the regenerator housing and a second valve attached to the second end of the regenerator housing, the first valve and second valve each comprising a plurality of apertures spaced apart from each other along the circumferential direction with each aperture positioned adjacent to one of the pair of openings of one of the plurality of chambers;

a magnetic device positioned proximate to the regenerator housing and extending along the axial direction, the magnetic device creating a magnetic field of decreasing magnetic flux along the axial direction as the Curie temperature ranges increase, the magnetic device positioned so that one or more of the plurality of working units are moved in and out of the magnetic field as the regenerator housing is rotated about the axial direction; and

a pair of seals comprising a first seal positioned adjacent to the first valve and a second seal adjacent to the second valve such that the regenerator housing and the pair of valves are rotatable relative to the pair of seals, the first seal and the second seal each comprising a pair of ports positioned in an opposing manner relative to each other and also positioned so that each port can selectively align with at least one of the pair of openings of the plurality of chambers as the regenerator housing is rotated about the axial direction.

11. The heat pump system of claim 10, wherein the regenerator housing defines a radial direction and further comprises a cavity positioned radially-inward of the plurality of chambers, wherein the magnetic device is positioned within the cavity of the regenerator housing.

12. The heat pump system of claim 11, wherein the magnetic device comprises a plurality of magnets arranged in the shape of an arc and configured to project a magnetic field substantially along a radially-outward direction.

13. The heat pump system of claim 12, wherein the plurality of magnets are arranged in a HalBach array.

14. The heat pump system of claim 10, wherein the magnetic flux decreases in a substantially linear manner along the axial direction.

15. The heat pump system of claim 10, wherein a rate of decrease of the magnetic flux of the magnetic field along the axial direction is substantially equal to the absolute value of the rate of increase in the Curie temperature ranges of the plurality of stages along the axial direction.

16. The heat pump system of claim 10, wherein the magnetic device comprises one or more magnets, and wherein the one or more magnets have a thickness along a radial direction defined by the regenerator housing, the thickness of the one or more magnets decreasing along the axial direction.

17. The heat pump system of claim 10, wherein the Curie temperature ranges of the plurality of stages overlap between stages that are adjacent along the axial direction.

18. The heat pump system of claim 10, wherein the magnetic device comprises an electromagnet.

19. A refrigerator appliance comprising the heat pump system of claim 10.